Method of producing magnesium-silicon alloy



Patented July 13 192% v UNITED STATES PATENT OFFICE.

SCHMIDT, OI BITTEBJELD, GERMANY, 48816103 '20 I. G. FAB-BEHIND!!!- 'rnm AKTIINGBBILLSOHLIT, OF rmxronr-on-mm, Gm.

mxon OI PBODUOIR G IAGKBBIUH-BRIOON ALLOY.

36 Drawing. Application filed November 15, 182 3, serial Io. 674,856, and in Germany Ievember 17, 198 8 or by introducing quartz meal into'fluidmagnesium and heating the melt to the temperature of reaction. This reaction mainly proceeds according to the formula:

The magnesium silicide thus obtained is dissolved in the metal in excess. This method embodies several drawbacks, one of which is the considerable loss in magnesium, half of'which is converted into magnesia. Moreover, unreduced particles of silica remain in the alloy, such particles exerting an obnoxious influence, when the alloy is subjected to mechanical treatment.

It is further possible to produce alloys of the kind aforesaid by directly adding silicon to molten ma esium. owever', this manner of proceeding also involves eat disadvantages, insomuch as it uires ing to .high temperatures, where y a great percentage of ma esium is oxidized or distilled over. The gh p1;ice of elementary silicon also acts towards rendering this method uncommercial.

It is well known to those skilled in the art that molten ferro-silicon is capable of takmg up magnesium and-forming alloys of magnesium, Iron and silicon, the constitution of which has not as yet been 'ascertained. v I

I have now. discovered that the addition of greater uantities of magnesium to alloys (for instance 0.04 uma) that amof the kin mentioned has the unexpected .efiect of displacing the iron int-he alloys to such an extent that a separation of the al- 10y into a ma esium sili 'n' alloy on "the one hand and non on the er hand takes place. As a rule, this'will occur the easier, the her, ranging from about 20 to 80 per cent icon, the --percentage of silicon in the ferrosili'con employed and; the greater the percentage of m esium in. the alloy of magnesium and a con. At the end ofthe "reaction, the alloy only contains so:- little eatpractically be regarded asbeing entirely. free from iron. In order to prevent the iron, which separates out, from being mechanically included, I prefer removing it during the formation of the alloy by acting upon; it with a slag-forming salt, for instance magnesium chloride.

In practisin my invention, I may for instance rocee as follows I ad to the molten ma esium the predetermined quantity of erro-silicon, this ferro-silicon containing from to per cent silicon; preferably the molten alloy is slightly overheated. v

To this latter end, I add to a certain quantity of molten magnesium such quantities of preferably finely ground and powdered.

ferro-silicon as are required by the desired percentage of silicon in the alloy to formed, the reaction being, based solely on the amount of silicon contained in the ferrosilicon. For instance a feud-silicon of 33.8% Si will react according to the formula taining' 50% silicon, the powder being thoroughly mixed with the melt. The reaction which setsin immediately results inv the formation of about 4 kilos of silicide of ma esium (Mg,Si), which remains dissolve in the magnesium 1n excess, the alloy containmg about 10% of silicon, as desired, while the iron remains undissolved and may be a removed in any suitable manner, referably by addin a slag-forming salt suc a s magnesium-c loride,. as mentioned above.

Thehigher the desired percen of silicon in the terminal product, the higher-the melt should be heated during the formation of Mg,Si. I have found that the most "fav orabletemperature of reaction rises steadily from 650 to 900 C. for a desired percentage of from 0 to 15% of silicon, a tem rature of 900? 0. corresponding to 15% con iuthetermnalproduct. ,1ncarrying out my invention, I do not wish to be bound to these temperatures.

By thus proceeding, I obtain in a simple manner alloys of magnesium and silicon containing up to 15 percent silicon.

I wish it to be understood that I do not desire to be limited to the exact proportions and sequences of operations described, for obvious modifications will occur to a person skilled in the art.

I claim 1. The method of producing alloys of magnesium and silicon containing up to 15 percent silicon and being technically free from iron comprising causing a compound containing iron and at least 20 per cent silicon to react with an excess of molten metallic magnesium.

2. The method of producing alloys of magnesium and silicon containin up to 15 percent silicon and being technically free from iron, comprising causing a compound containing iron and at least 20 per cent silicon to react with an excess of molten metallic magnesium and removing the iron displaced.

3. The method of producing alloys of magnesium and silicon containin up to 15 percent silicon and being technically free from iron comprising causing ferro-silicon to react with an excess of molten metallic magnesium.

4. The method of producing alloys of magnesium and silicon containing up to 15 percent silicon and being technically free from iron comprising causing ferro-silicon containing at least 35 percent silicon to react with an excess of molten metallic magnesium.

5. The method of producing alloys of magnesium and silicon containing up to 15 percent silicon and being technically free from iron, comprising introducing ferro- SlllCOl'l into an excess of molten magnesium and slightly overheatmg the melt.

6.The method of producing alloys of magnesium and silicon containing up to 15 percent silicon and being technically free from iron, comprising introducing ferrosilicon powder into an excess of molten magnesium and slightly overheating the melt, the quantity of ferro-silicon employed being slightly in excess of the theoretical uantity.

7. The method of producing alloys of magnesium and silicon containing up to 15 percent silicon and being technically free from iron, comprising adding to 10 parts by weight of molten magnesium 2.5 parts of finely powdered ferro-silicon containing about 50 percent silicon, thoroughly mixing the powder with the molten metal and removing the iron.

8. The method of producing alloys of magnesium and silicon containing 11 to 15 percent silicon and being technicaly free from iron, comprising heating 10 parts b weight of magnesium to about 800 (3., ad ing 2.5 parts of finely powdered ferro-silicon containing about. 50 percent silicon, thoroughly mixing the powder with the molten metal and adding a slag-forming salt to remove the iron.

9. The method of producing alloys of magnesium and silicon containing up to 15 percent silicon and being technically free from iron, comprising heating 10 parts by weight of magnesium to about 800 0., adding 2.5 parts of finely powdered ferro-silicon containing about 50 percent silicon, thoroughly mixing the powder with the molten metal and adding magnesium chloride to remove the iron.

In testimony whereof I afiix my si nature.

WALTHER soHifInT. 

